ILIAS-N4

1. Integrated Large Infrastructures for Astroparticle Science ILIAS-N4 • Search on Double Beta decay • Coordination of double beta decay searches • Bank of pure isotopes • Negociations with Russian labs • Theoretical developments

6. WP1 Deliverable: Final report on background issues http://idea.dipscfm.uninsubria.it/frontend/exec.php?id_folder=22

7. GERDA A major improvement in sensitivity compared to previous experiments can only be achieved by a reduction of the level background. Present level (IGEX and Heidelberg-Moscow experiments) 10-1 counts/(kg·keV·y) at 2039 keV GERDA phase I (15 kg of existing 76Ge diodes from the IGEX and HM envisaged background index 10-2 cts/(kg·keV·y). GERDA phase II (40 kg of enriched Ge76). Minimization of cosmic ray exposure and segmented detector readout will help to reduce the background index by another order of magnitude. If phase I and II do not show positive evidence for 2b0n -decay, an O(500 kg) experiment would be necessary to reach the 10 meV scale for the effective neutrino mass. For background-free operation of such an experiment it is necessary to suppress the background index below 10-3 counts/(kg·keV·y). The background suppression techniques developed in phase I and II of GERDA will show the way to such a large scale background-free experiment that can only be performed in a worldwide collaboration.

8. Cuoricino-CUORE Figure 1: CUORICINO background in the 2b0n region. From left to right are visible: 238U 2448 keV peak, 60Co 1173+1332 keV peak, 232Th 2615 keV peak. The2b0n-decay signal is expected around 2530 keV.

9. The present results are: - successful selection of most materials with the desired radiopurity , - high sensitivity fast technique to analyze special materials (lead and copper), - surface treatment procedure with ultra pure materials to remove any contamination from crystals and copper surfaces (both the procedures can probably be exported to other kind of crystals and materials), The global result achieved after employing these techniques was the reduction of the background level by a factor at least 2 with respect to CUORICINO . A study of the origin of the residual background being on the way. Once projected into CUORE, whose structure was designed in order to minimize the more critic contribution to background such as those due to surface contaminations, the resulting background is of about 2-4 10-2 count/(keV.kg.y).

10. NEMO Using simulation, for each kind of background, the number of expected events in the window 2.8-3.2 MeV for the 100Mo source is estimated to 1.5 10-3 counts/(keV.kg.y).The contribution to this background is: 7 10-4 counts/(keV.kg.y) of 100Mo 2b2n-decay, 4 10-4 counts/(keV.kg.y) due to 214Bi coming from radon, 3 10-4 counts/(keV.kg.y) given by 208Tl contaminations in 2b0n sources, 5 10-5 counts/(keV.kg.y) due to the external neutrons and high-energy g-rays. 3 10-6 counts/(keV.kg.y) produced by 214Bi and 208Tl in the glass of the PMTs,

11. Figure 2: NEMO Experiment - two-electron energy sum spectrum for bb like emitted from 100Mo sources.

12. SuperNEMO The sources activities should be less than 2 mBq/kg for 208Tl 10 mBq/kg for 214Bi in the case of the Se82 source (300 mBq in the case of Nd150, so much lower constraint for radon). For all the materials of the detector, including radon (except in the case of Nd150) and the glass of the PMTs, the activities should be divided by a factor 10. With such specification the total background will be 5 10-5 counts/(keV.kg.y). The objective is to reach a sensitivity on the effective Majorana mass of neutrino of ~ 50 meV.

13. Bank of pure isotopes. Ezio Previtali, Piero Benetti, Massimiliano Clemenza, Dominique Lalanne Co-ordinator : E. Previtali, INFN, Milano, Italy Deputy Co-ordinator: D. Lalanne, LAL, IN2P3, France Some new production of isotopes : 2 kg of enriched selenium for NEMO GERDA experiment had received in the last June 37.5 kg of germanium The Ion Cyclotron Resonance (ICR) approach was presented to the ILIAS community and a Letter of Intent (LOI) was prepared for a Design Study (DS) to be submitted to the 7th Framework Program (FP7)

14. ICR Costing, Timescale. Experts from CEA have estimated in 12 million Euros the cost of an ICR, including also the personnel, having a throughput of 100 kg/year/isotope, at 50% of enrichment level and starting with an isotopic abundance around 5%. Different raw material inputs or isotopic enrichments are possible and the throughput will change accordingly. The unit should be operating within 5 years, design phase included. ICR Applications. The production of isotopes can be crucial for many applications in physics and in other sciences: we will try to indicate some possible interesting items that can be potentially covered with a dedicated ICR facility: Double beta decay: many interesting isotopes can be enriched; in particular 48Ca and 150Nd can be produced with a reasonable throughput, while other techniques show no chance or very little capabilities.

15. Medicine: stable isotopes for diagnostic and therapeutic applications can be prepared: in particular some interesting stable precursors of radioactive elements can be easily prepared. A very short list can contain: 112Cd, 50Cr, 102Pd, 58Fe, 203Th,… In particular the ICR machine of Theragenics was specifically built with the DOE support for 102Pd enrichment. Nuclear industries: in future high quantities of 157Gd, 64Zn, 90Zr, 58Ni, 54Fe, 97Mo, … will be requested. Scientific research: some enriched isotopes are of specific interest for some research activities: 43Ca, 168Yb, 44Ca, 48Ca, 58Ni, 50Cr, 76Ge, 82Se, 150Nd, 100Mo,…

16. Negociations with Russian labs for Se82 production Tender in June 2006 for a production of 1.5 kilo of enriched Se82 ECP-Krasnoyarsk… …and SURPRISE : a second answer : Chemgas (France) Choice done for Chemgas (better price) According the procedure, not possible to make a different choice

17. All possible sites in Russia are (and Chemgas is in touch with all of them) : For Se82, it seems the choice of Chemgas is Tomsk Actually Alexander Barabash thinks that the 2 kilos tagged « ITEP-Kurchatov » were produced in Tomsk (September 2006 announcement !). Question: did he really know that long ago or not, but at my last questioning in June 2006 at Santa Fe he confirmed me that the 2 physicists of Kurchatov were doing the job. (But I have still no report on this from Kurchatov (!))

18. MENPHIS reconversion to 150Nd 3 phases : Phase 1 : 6 months, 2 persons, study of new parameters : report done Present situation : under discussion between CEA and IN2P3 decision of CEA not yet made, but dismantling is the first option real issue : a framework of funding and manpower IF POSITIVE DECISION : Phase 2 : restart of the facility, new collector to be designed tests with new lasers, purchasing of 3 tons of natural Nd (2007-2008) POSSIBLE PRODUCTION OF A FEW KILOS (up to 10…) Phase 3 : tests, tuning, running (2009)

19. Recent news • study of Commissariat à l’énergie atomique (CEA) on the feasibility • of enrichment of Nd150 • -International statement for a large production • (SNO+, Moon, SuperNEMO, DCBA), July 2006 • Strong letters of support for a Nd150 production from • Art Mac Donald (SNO+) and Frank Avignone • - Discussions between IN2P3 and CEA on the subject

20. Letter of Interest for Double Beta Decay Experiments with Neodymium 150 July 2006 Signatories : José Díaz (Spain), Juan-Jose Gomez (Spain), Serge Jullian (France), Dominique Lalanne (France), Karol Lang (Texas, USA), Julio Morales (Spain), Fabrice Piquemal (France), Ruben Saakyan (UK), Federico Sánchez (Spain), (SuperNEMO collaboration) Josh Klein (Texas), Gene Beier (Pensylvania), (SNO+ collaboration) Richard Hahn, Minfang Yeh (Brookhaven National Laboratory, USA, SNO+) Mark Chen, Aksel Hallin, Aksel Hallin, Christine Kraus, Art McDonald, Peter Skensved, (Queen's University, Canada, SNO+) Clarence Virture (Laurentian University, Canada, SNO+) Franz von Feilitzsch (Germany), SNO+ collaboration Hiro Ejiri (Japan), Masaharu Nomachi (Japan), Masher Monarchy (Japan), (MOON collaboration) Nabuhiro Ishihara (Japan), (DCBA collaboration)

21. Theoretical studies NDM06 Symposium in Paris, November 3-9, 2006: very interesting discussions between theoreticians on the comparison of QRPA and shell model calculations see web site http:// Work on NME in Tuebingen, Bratislava and Jyväskylä groups

22. Tuebingen group • Faessler, M. Gozdz, V. Rodin, M.Y. Saleh, F. Šimkovic, R. Dvornický, • P. Beneš, • The continuum-QRPA, which is the most advanced version of the QRPA, has been developed for the first time to calculate 2nbb-decay and 0nbb-decay amplitudes. A systematic analysis of the double-beta decaying nuclei is being performed within the approach. Calculation results for 130Te and 76Ge

23. Bratislava and Tuebingen groups. A version of the QRPA for deformed nuclei is being currently developed to take into account realistic residual interactions The ultimate goal of this activity is to calculate 0nbb-decay nuclear matrix elements for such an interesting candidate as 150Nd. The calculation of the QRPA Hamilton matrices is in progress.

24. Jyväskylä theory group J.Suhonen, M.Kortelainen, J.Toivanen The calculation of nuclear matrix elements for neutrinoless double beta decay has been focused on means of testing the underlying theory frameworks with independent data. This independent data comes from beta decays, the nuclear muon capture and charge-exchange reactions.